<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>

	<body>
		<script>
			var name = "abedchshuaahdhdh";
			var acount = 0;
			var weizhi = name.indexOf("a");
			while(weizhi != -1) {
				weizhi = name.indexOf("a", weizhi + 1);
				acount++;
			}
			alert(acount);
		</script>
	</body>

</html>